Gang experts in Houston estimate 75 of the city's 300 murders last year were gang-related. A much smaller number is directly linked to MS-13, the Central American gang believed to be connected to the killing and dumping of Genesis Cornejo.

While the numbers of MS-13 murders may not be rising, their level of brutality is.

FBI Supervisory Special Agent Mark Sabol, who works with the Texas Anti-Gang Center, told ABC13 Investigates, "These are some of the most graphic things we've encountered."

MS-13 came up from the streets of El Salvador. To understand the violence the gang is committing here in Houston, experts told ABC13 you have to understand how violent their lives are there. El Salvador has fewer people than metro Houston, but 16 times as many killings.

There were more than 6,500 murders in El Salvador last year -- Houston and Harris County had just more than 400.

"To become a MS-13 member, you must commit at least one murder, sometimes more," Sabol said.

That may be as close to a motive as there is.

"There isn't a group wide endeavor except killing people," he added.

According to Sabol, MS-13 doesn't deal drugs, or traffic in guns, money or migrants.

Their victims are not random, either. They are typically gang associates. In some cases, like Jose Meraz's, they are people who want out of the gang life. That's not possible because you have to kill to get in and die to get out, according to experts.